SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a5b935468207549e939736d43d297f6b4eb27fccbb38e7ec1a17e2ad1f74705' 
  AND token = 'a02Xskt/qYvvzUGusfBnX17W/aQVaFgGagczaIKR/T4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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