SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c357c1c45f3961a918520cab9fdb5557450ba7c247888aa554836f486ac4f96' 
  AND token = 'Vunm1vyBIoIS66qf/ajkCoZWfwNPZCoCUHBnJ4Tn6Ag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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