SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4ffd75971bfca80e9a133a4826118135aec3a836aecf067926c2942a004e5de' 
  AND token = 'h7dNc/YyJZigywEIpq7KjivpM+4q5uyQxNl7HMcjH7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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