SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e6e4f01c717e2056b62785ac99a4d872058c6676143b9114361cf06ed746174' 
  AND token = 'XlmPqRKTCNqQPv4TPsLWusP5UfuUoiBSewiEhyc8tcA=' 
  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"
    }
  }
}