SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ffa288ebf82a4036b21a07c867d698f351601c1b7a4d0e90f7aa8e1f67887a8' 
  AND token = '7vENiwpk4uHluhtlvRlepP4EpDYWJ/K6UcBVFG9Dpqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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