SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a90307cc23c7bfae3db92753e84e2e281ad60479b62a8687883cd593a5624c53' 
  AND token = 'FibQz/GqkMDJ0qXnDZI64gENMwNjIgBntamMv98wZLA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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