SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c90380c59904fc45b6e1041c6de261e5271ef57d60c6cd1b4f7ca793bd5c0c4c' 
  AND token = 'aOQzL1Nlpb4oNJmgkIoNMpE4yq7if3TKqvil9eEiUJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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