SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65298a89bc21992e35fe2b6a15828d866046aaef778d474cc10f009dd91efb8a' 
  AND token = 'robVHXt62C0R78n+WeRQHDnWHdWpalE+VPXWSKM8YTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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