SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bdf3e82ad21b4819f8021eeb665b66dd411755d010134e7847cfe905818411e8' 
  AND token = 'rKgpxZyj6OQUXxBiXmVtjskvSlUAKVxx1+45/h3vT2o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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