SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f5d8becd8b4e069ce032126d9893e00e039b194fe3adcc228ea0ca39118e80b' 
  AND token = 'fMbpmvS5aMy1o3yVb3lRGK3TgmTPDDFnnPmdtAQoHUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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