SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '012976683fc5b1968259e8563cb43cedca5a3f0220c7744926afa7a61dbc7eb3' 
  AND token = 'XDFFXvpTM76PmL5uXAMDmKXjXslH+CDcazTGomptLjs=' 
  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"
    }
  }
}