SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '00cb8446704dd86b8097d7996453e6678c4be1a7a63ad44904e21c081cdce1db' 
  AND token = 'keeGzdGjbtO2F8DSJoPGJFjZH74WYlmJepmCmis87XI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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