SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2951a7aff280ca2bad9f02ee1a8fd043a411d8cc4e58e56ee984606b669068e3' 
  AND token = 'nmjCRyILOVbHAvLsgp8RncX51WXszjCoCjbaUUmzMKw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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