SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd754c91e3467de6dda4b7ffef0fc99eca35a013cb1edc5fb4795b118fd46eee8' 
  AND token = 'ScYxPD/YSSN+n9ZtkfprJW1p/rTrM2F/oHIqlazO0IE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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