SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6c035cddcf18da026cf70c061a2f015b2fd9be72a046a33922bd67ae481709c' 
  AND token = 'veCeZgdd0Q4K+LwFLWZVKDHpOu/tuWm0SQ7z+FRmStE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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