SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd3dd7c12cd88797ac35b1b4dd630531c4a0ca16ddbfe8a2a85ee2817be7e1de0' 
  AND token = 'qV+lCTAFqd9y1l4qMbBxUzpM9lK5F3ULRBZNSGuAWl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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