SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6de02f94408e8e55099f8fb62e5af09a0cab449cda24d558bbabc436a64271bb' 
  AND token = 'fD/pFqvi8ohNMuRC3CKVCpW31Sk66B/KnWk8bJe5Dgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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