SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc0530c6dc2eae638fe77f23cc31219db98e801db19cabe58e7546455530ba53' 
  AND token = 'uNzsZetCP3RfMhCQP8N+5MxoYCa1gYthteGGvHvEUzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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