SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf57cc4e8352f184e317bb5cda6d54ec0b5265a7487d5fee9db9c31028583142' 
  AND token = 'jdDJQSyk5a6rPod/Cona2ay02uETnnq6okrSHLjhJXY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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