SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f35a2e0ec5e2318540ca32fc896448d8dacf5e0a4fb2a5485da90c47a5cd456f' 
  AND token = 'CqrwzuhaAjcb/P7ZCJtBkZfyvU7BqP8YpZsISk+1xFI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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