SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e2c1eab6209c92c53b6c4544fb5a4b5313a8d7d3c06b9cfa47b9380f99f0082' 
  AND token = 'EXnuOIv7RdrnJ3W98PKMCr+dkm0VPvayHYI/Z+sNaic=' 
  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"
    }
  }
}