SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0762fbc14a1f97043ef76f6451f268a530a8406770f2f10ba9258653deabe162' 
  AND token = 'vJQDrzQBURBZv8+ajE0LFN2cEbawGkA+S79OuduO1wM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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