SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da6585cfaaa9e0a51febf3b5e1b4e27cdddc4f9d28efaadac9d1c23daf5b7d58' 
  AND token = 'G/Azv6UmR22UQhHKTVqJoUwVALO/by3XKMFZ3lou9dE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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