SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd551f64d5c047dfa289884a12b7edcfa4d718e4149c4bbfb33233e0e717f60ca' 
  AND token = '3n+gJoGcNH5RLj9Vmqk5xt9/h0/k+1jnqFsrMkFG2Us=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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