SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c1ac71d6b59843f1df103be95384a587a8e76d6aa1b0dd6c4548fca96727089' 
  AND token = 'TT6S+jWOZ5pXAT6aGLwyIGv0humtwEZ1Mkf8NY/tAEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}