SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ea5191758c4f53a04de04dbeaff185d2d3ac4b2693ba816099c9786b41da3bfb' 
  AND token = 'Amb6UxOhipBIJbiegcExsA6DYPtJ/pgz+oRuZEZhrqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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