SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b471a4dc4a57997a9c5b387155b17686142b0f327008e51082220d3f9d40a14' 
  AND token = 'jsYnoJp8Nms3XMKR1f2lIZkXr1VOCH+pW76MOzvO6W4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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