SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a63cc0489d01ccb9c2bd0891553706421fdec9e6659de478116d44761fda4f79' 
  AND token = 'MB5xyO56d4HmbyAssQCxI/x6Ign8q7St2NW6ACvvPog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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