SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b61fbf6362083bfdb9c7d16fc7fc7241a902cdc9bfde0d3f999982f2781ed4e0' 
  AND token = 'JOkApU+dwj1BUHtBKeMPATuUDyy3CsjTzYmn9lE7Xtc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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