SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a65307bc19256f7c9531a264f4e368a2a4fa9be44b528175d4d1d159300167bb' 
  AND token = '309pdvaQKwd2zgxVPI7fMxBEpFKtZPKJazhMXdywKTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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