SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '644aba290fdfce0b7975a1f7e1a0481b86abed5d2be633cbd073bdfb1c3a8f9e' 
  AND token = 'y/AWfHr+eBH84hCjKXrf0zUScHRjI7l47UDC12v9qts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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