SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb6672df5085cbfcff24186353839ed38fb1591bf1076886f24a8d2bb8780692' 
  AND token = 'nl4K62GcZkTR8aXtSWSkmkA9OfxSzbdN1nAfFIc2gpc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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