SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5deb95341d40011cb640db3a1b9d27716aed12b6bbae0ad2d7a245cfb67847cc' 
  AND token = '9dwXbPWkhGmRPSLnPMC2IR6SrOMmXjlSpLEjPaFM9sk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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