SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f32a3306e8f91a06457472515b390f8ea5a8c1025c226579ed6ca31b17ad971' 
  AND token = 'T+idnCaf6xRV1xRVMj351dIo0J+dE8IH0Je//sEEKWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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