SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a4bc35fd6dc517f4619e7734441fdbf0bdf65faf62eaa97daab8ccd5f2f0349' 
  AND token = 'dZbZMP79p22csffFkBXat6hnAvLYwULTzM+Bb+ta8rk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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