SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb854c9f8a9d40403e43837bacbf6d9b9ff3221d9e19ff56029c0093a7b5e7e4' 
  AND token = 'nnJjwjNPblo9xImSH17E4Wx2mgGSYn8fwdVVhGhjPQw=' 
  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"
    }
  }
}