SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e8acb7160bb20b6143586adebe8257cbd24d066fcad5e292e8a9a7fc84f6ec75' 
  AND token = '3NWVBLifU4WptgEeQRfLLekxIcfUoIkpE2sAjGOIesw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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