SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2db638f0c45eb282ea1c1c9b27cdcfce240acf24954420b938953af1caccaf0b' 
  AND token = 'Ni7Dv9QiJBXPGkxdRH8P07ijIhDwulyxhKszELwA/xg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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