SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82262f5e24f4217ee8449f83cc29729bdf70a9e8b56d646abb660af4648bc247' 
  AND token = 'VnHe1WhC3XZ/iiM7Jwj4pQ5tobtKpGJPA1VUltsLnPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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