SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f68cb4d4ccb5d9d1feb881db0f5b02c559e560282b27cca38888da303230f78' 
  AND token = 'wGc542CeKs3v+EDgqU/DqBGR7esBs4Nh56fXHHVNhaI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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