SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9a9a9daf341cc7086849c131fa5fd9d8dad99c9709cac26c640fc815f32b417' 
  AND token = 'eifwkxtOLSMCLdJ/DeXwqka7ltzEgwhskctcLKXAUtY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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