SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f820d8cb6a40f3e49c61de61e450e46b2cb812a12acc511456933bafa549e130' 
  AND token = 'lh/KFVHuwd4VF7979m4SbtAdVpCjAr+UgyviDffFz8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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