SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efcadadf3baa9028ffd54059b1b96e0aafb73e79ed8b7445846311ed77c8508c' 
  AND token = 'R6MhI8EfLupqrJf8qcYQuUeaaeJfQIvc0uX5HKpfgqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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