SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5df83ee1c5de44e86a280541402f3705b8eaaf0dd07bff3a83e9c654149579c9' 
  AND token = 'qk/v7aWNwRCGDk6zK0qaftZmuwXY7/3BSWZTrg1plS0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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