SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f22cd2e67f4dd32f94cfd8aed536a2398df15712a0d61e41fbce9c76751c2b6' 
  AND token = 'mnhFjnuPrh1aSZK2oI1Yy4mIECAUQQrVPuHlcueigDs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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