SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0ec4e32107d98934225c6ead72d206dadca566eb0d22a0edf33c35ba8391a9c' 
  AND token = '4f8tiKgVn1KJEuXM2GWGDq3EZ6ljrAAzHcHYqGwGzvM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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