SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1fde98dc9843ab34938a0b66a76b4bc30241b665acfc5b4d4314d39ff9c32a98' 
  AND token = 'u0vp272j9VQMJYEihWHdprKzokRheKOQWyQKORm9N1k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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