SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ebb4ea9cc9dcd52c020f06fe6696f7f7e0254da412dd4df43ef1d4d3478a46b' 
  AND token = 'otArDYYAsRaYUx1vOKyFNh5jBf5LUZVvUAYjHizzmmc=' 
  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"
    }
  }
}