SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be288d59f459d677b21d573c6478c8b5ee285192aef112bb3019f8e04febd4af' 
  AND token = 'k2zNnpG2uN9ngup2AJL/nYAoCgIIQVf9lKSwLcXE5Y0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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