SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '712ec082acd264a7eb52eb083e8cbde63a2153f159fe865c7f5fcb9398fe5e26' 
  AND token = '/LTzvW9j+nyrKAh7xmdsWAD21MsZqGXMCx36PNBVpUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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