SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a3266461fdf0f89219867c2c874125ed0528fbad72a74751adfbdc9eb51acd7a' 
  AND token = '+eHpsUYtSyKTP4NXE11LMOAWK8MhRQHPQNWRNFDm2Ok=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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