SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2165d48b4815e6465fc08d3e078650065ea6decdb25f278e17f57d142be9695' 
  AND token = 'aH1zDVGiJ0+tRagqiCrllc0ig7Fnn9YpBvwXo/coDSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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