SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8e8ca9d168e1c15cdf492f67851c39c7a0dfebc0043d34cd85eab92806172b02' 
  AND token = 'YQwxZES7Hbv1rLYsuyZsI30iYQA4X4t4sQMET+UnURc=' 
  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"
    }
  }
}