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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cadda8e386859490672dfff03f7e55ab93eab02cadbbb4e8e0a2a2fca208b3c5' 
  AND token = '3aNGqFpY+FOfXb3yxwMaWQRsV/TrXA5RnnUZ5+Vr3xA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}