SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37c40c33d0138d419b12f137ad68949ef0fb6108d0e5a6b5ebeb2799278c255d' 
  AND token = '/lLat7dm/bWQ1lyoQrX1hp40oe9IpPfzznnSF7deda4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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