SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70ad74b543a77cbad1785f49794920db8249fe6f2aedaae11641c467d85f4ec5' 
  AND token = 'LnkFMlKXlL2F7YFXHC41ynXqZFsSDAV0jUVZX22KVG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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