SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29e90af858ec61c0f0ecbff268d5b1dc6ada75023b59cc821b6fc712f3b470e2' 
  AND token = '4FyDrYS4+lW2L2Mg22UmQbV0hvYWQra0ZmMNGLSv1Ls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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