SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8cf1d74965f109ca9209ddcb3d833aa95f532c28fd2abf5794e2b550d3267b7a' 
  AND token = 'NBcv1uSZHjIXkSktEzPpMGwWwDdiiM1vvY5HuyeaMQY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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