SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '543482e92368b46fd432161606a37649be754b00f7be075bbc36710cd9679e76' 
  AND token = 'LlF94CBuOvp2fHD+sC/gqOXzfBd5uyj1JEMcpErcQx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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