SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bec95147d7487ac47f284786079ab6d41d7502f60113a07d220b143499cb137' 
  AND token = 'e9WPynApgM1Zqp+9500sl5+NBXprovbLihgPtUrwg5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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