SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aaae2b67d235c3cd19f4dd71d65ebdc872ae7b86220fdf5206d2205644fea3d0' 
  AND token = 'S8i/ByfY/rCepUxziTy/ivmZh4ZOUH+oDSocx8jd2/Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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