SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7645cab9a4194b3fe1748489172d156b40a235ca152fc09f49d5d4a9251cbb44' 
  AND token = '3r9LjJN4Gtqzd27ZXbdzHQYNlB3vV24pb4IdwK7UY8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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