SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78b1c9d213150ee3ea1380465081f5c18d587583b85ffafbcb6cdccbdfdfb93c' 
  AND token = 'hqQLF2MeK+uG83hH8C4GHnHJkft9JsGKp/QCNB2hAYo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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