SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '148d6e05a2ca267481ea84e2ee8e81fba6c2c3f8ddfa9ebe2e4ad55687cfe684' 
  AND token = '9mMgeYlk+MFZEpR4JSM/0XFkI4ukFl2sXK6AhMKm/1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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