SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bba68f12575dcc3d0404ea98f4f512a43700e05cf8b0f932263c6e861207a212' 
  AND token = 'wALqPmK5icDZJCRlWEZSUJBTyV+QRUP6/AUvQ/UjPUQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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