SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d3bfaa8ec14778203cee2f2c52270f07ba4496947519cccba0daa53fc546d59' 
  AND token = 'RMO/K5cG3MosnK0sZTD/Qwz9N+jB1aFJwVTtP5MwxSg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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