SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a62770b8cbc24d27948fd1fe66faf9d514ae841681705b4dfde79d4fd8d79d49' 
  AND token = 'VqleHiCOPaBHqzsyABCAgCrKt/3VQ4Eg2ZXXjecfEBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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