SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8a911dcd68507eff8aedf14bb34c5861e34813a30e66056cdc7adf029f3421e' 
  AND token = '1hTCvX5ZKMWgbpbi0eV+gxXjBc6PkQ1GTprA3qsLwCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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