SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '992685c0b3066f7536df0f41011ed70aed2ea56a24395fd920cdfc1f9c0c1164' 
  AND token = 'eRuxPhR5sKxHPV47ovpWXexZvKMcuStVkui8PR9YVUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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