SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9a8428f4486ae4d4763423ef18cbe93fd4353a6fe8befdaced01b00421c0b2d' 
  AND token = 'AEIo2zMZ+EMS6lzOTt069pRnZNEsBaYtngUasXwTWug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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