SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '361fe4022730ebec93d93225f82ee64cbf507008ff696aca2af19124019e2f3e' 
  AND token = '/0bDfq/PAFqICyO1+XbaYVmrL3a2HG4sAyWcBgruUOo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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