SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '596e748d3f36153a64b91c8e0fe159d42164854c388b461996717db80ee818cc' 
  AND token = 'iYcsn7a8+kQaNVuvaDVM1qVYrke+rS+tVubPgVDjXqg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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