SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd518bab7442531163888c5a9ec6b820acbcc1db65ed9d0e5fb24d498c701b696' 
  AND token = '9VOCPqc6BHt++wObfrggepp/ZVV/AkAGSvCEgpNIqtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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