SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed785395298e30e52b742c3add0309ae12334aad06ad715a6752eaf998510f84' 
  AND token = 'RlHGcIJz5u+mR5Pr1J0P/+HCEJrk7vCsqnkW8Mj+RdI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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