SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '997988e559999e6235cd8f192e751dcd19ea7f0f504dc691c4347dcafc9ab38f' 
  AND token = 'cCwXw4mm5wJohuYbTMEUKxmAFm4z9Bx5rNKwOYkQPDk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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