SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f04fd2cd58ee4268c29cd227967f8068bc1562483be4aff72d8e5193dbbc634' 
  AND token = 'VQcH/oxl67/MTW0RhWgJ03VnqzNC+PxXoT3dRnoWYG0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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