SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa7da33f342bffc192c945ea13c93ddfeec15651fe944b6924397ddcf9095b72' 
  AND token = 'K1YA2PtLmFe7lqPKcrgWEtVq1TMHXbEiKMuxWlanyrs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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