SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c41b0dcd902b0101072e8890289d5a1f301db06d41f91e69e534bbfeb3c6fb4b' 
  AND token = 'Yyk+DVUzbnY/dDftTZhHWwj3VJjPcg5X8HIQhY7CHtM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}