SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f2499639bff1bbb80b3804d3660a9f35685fb451eb641e09dc6e537c4eadbd8' 
  AND token = 'unmRtk8SHUfvtvYH8GTCqifsMPezrN2T2AZ4o99chz8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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