SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc3360bebfb913e298fd86a16cc1bcbc75f6e144dbb6018888dd887f7b791896' 
  AND token = 'RcZvDWpWVpRb9ZnFktdGnTCFU58icnTTFuA1O3zmKqk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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