SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcc35588ab4d5541ed4746b048c700d72a4336cebe46b81f036b80f65eb3e675' 
  AND token = '1RsYAi4SCuzWAMkR8zm+13Jdq5aXd6y49OnUTztY5q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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