SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cbcde765f91761380c6c76810d6209ae554aa45ce399fb9827e29b428727657' 
  AND token = 'RS2h8x6Wwbg2kFUYilIdsDsGdzzaLVEMFYQ8WoB4JGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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