SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8866b0d33ef3d85db3547cad8f800aebf6d77f86bc22948156a25c687e0f045c' 
  AND token = 'fFIkqSxKm5pejb9UPDl5+vKzPmQDO+xbtpR7PkOsFP8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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