SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3204f3e1ce7ccd1070003615906b87658f47cb7fbd4af6acad06b6f0f894590c' 
  AND token = 'F/WsLGHkBkYHCsLimAaqxRRKjhlUR+TcbxYkqwY7Nbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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