SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9f8952134aaa83d02793c9a0896066cf835da210f1857c8f4a3aead9bb9f8db' 
  AND token = 'pGlOO+57l6MVjCnc4AGykAOfb9LLF5rOI261mD1NYRY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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