SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '585bdac1cf3d0ad96a0fe43a96796cef11ebddbd3997a06c8071b3a51c41146d' 
  AND token = 'EajfaAt3OKfIu5ppFvuGRpUpS4sRKbD+0BRnx9BiKGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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